The expansion of ultrasound molecular imaging applications warrants a reduction in ultrasound contrast agent size and significant advancement in the in vivo stability of shell-stabilized bubbles. The shift from first to second-generation ultrasound contrast agents was marked by an improvement in stability as air was replaced by hydrophobic gases like perfluoropropane and sulfur hexafluoride. Further enhancements may be facilitated by focusing on strategies to retain the encapsulated gas within the ultrasound contrast agent shell despite extreme mechanical deformations. In this study, we developed a novel ultrasound contrast agent with a unique shell structure and a specially-formulated, low-boiling fluorinated liquid interior, resulting in superior stability during repeated and prolonged ultrasound-induced oscillations. Our ultra-stable nanodroplets can withstand sustained in vitro ultrasound exposure with minimal signal attenuation and can induce significant signal enhancement and delay in signal attenuation in the kidney, liver, and tumor tissues during in vivo experiments. Furthermore, encapsulating photosensitizers within these nanodroplets and leveraging photothermal effects could further augment the ultrasound imaging signal and verify its efficacy in tumor therapy. The creation of highly stable nanodroplets opens immense potential to augment the role of ultrasound in molecular imaging, therapy, and drug delivery.

中文翻译：

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具有低汽化阈值的负载混合液体的超稳定氟化共聚肽纳米滴


超声分子成像应用的扩展保证了超声造影剂尺寸的减小以及壳稳定气泡的体内稳定性的显着进步。从第一代超声造影剂到第二代超声造影剂的转变的特点是稳定性的提高，因为空气被全氟丙烷和六氟化硫等疏水性气体取代。尽管存在极端的机械变形，但通过关注将封装气体保留在超声造影剂壳内的策略，可以促进进一步的增强。在这项研究中，我们开发了一种新型超声造影剂，具有独特的外壳结构和特殊配方的低沸点氟化液体内部，在重复和长时间超声引起的振荡过程中具有卓越的稳定性。我们的超稳定纳米液滴可以承受持续的体外超声暴露，信号衰减最小，并且可以在体内实验期间在肾脏、肝脏和肿瘤组织中诱导显着的信号增强和信号衰减延迟。此外，将光敏剂封装在这些纳米液滴中并利用光热效应可以进一步增强超声成像信号并验证其在肿瘤治疗中的功效。高度稳定的纳米液滴的产生为增强超声波在分子成像、治疗和药物输送中的作用开辟了巨大的潜力。